乙酰胆碱和组织胺对豚鼠离体气管条张力的影响及机制分析

The effects and its mechanism of acetylcholine and histamine on tension of isolated tracheal smooth muscle in guimea-pig

用自制的多个“工”形相连的豚鼠气管条,观察乙酰胆碱、组织胺和异丙基肾上腺素对肌张力的影响,探讨钙激活钾(KC_a)通道功能的变化。结果显示:1.乙酰胆碱和组织胺共同作用时,平滑肌张力升高幅度大于乙酰胆碱和组织胺单独作用,小于两者单独作用之和。2.异丙基肾上腺素引起乙酰胆碱或组织胺所致平滑肌张力下降,甚至低于基础张力,乙酰胆碱和组织胺共同作用时,异丙基肾上腺素也可解痉。结果提示:中等浓度乙酰胆碱和组织胺对增加气管平滑肌张力有协同作用。异丙基肾上腺素引起乙酰胆碱或组织胺所致平滑肌张力下降,表明乙酰胆碱和组织胺引起气管平滑肌痉挛时,KC_a通道处于关闭或大部分关闭状态。

The effects of acetylchoiine(Ach),histamine and isoprenaline on the tension and the activity of Ca2+ -activated k+(Kca) channels were studied in guinea-pig isolated tracheal strip cosisting of some'z'shapes designed by ourselves,The results showed that:1.The tension evoked by Ach and histmine had increased over evoked by Ach or histamine but decreased below the sum of the tension evoked by Ach and histamine respectively. 2. The tension evoked by Ach was abolished by isoprenaline and even below the basictension. The tension evoked by Ach and histamine together was also abolished by isoprenaline. It suggested that Ach and histamine in meddle concentration had synergiem on increment in tension of tracheal smooth muscle and Kca channels closed or mostly closed while tracheal spasm evoked by Ach or histamin.